Motor vehicle that acquires driving power for running from high voltage power supply

ABSTRACT

A motor vehicle acquires driving power for running from a high voltage power supply. The vehicle has a collision detecting device that detects a vehicle collision, a deceleration detecting device that detects a deceleration of the motor vehicle, and a high voltage system shut-off control device that provides control such that a circuit of the high voltage power supply is broken in response to a collision detection signal from the collision detecting device. The circuit of the high voltage power supply is reconnected when the deceleration detected by the deceleration detecting device does not become equal to or greater than a predetermined value within a short period of time from the receipt of the collision detection signal. Therefore, if the vehicle has collided, the power supply is shut off immediately, and if the vehicle has not really collided, the power supply is not shut off so as to surely enable the vehicle to run.

This no-provisional application claims priority under 35 U.S.C. §119(a)on patent application Ser. No. 2001-148851 filed in Japan on May 18,2001, patent application Ser. No. 2001-185495 filed in Japan on Jun. 19,2001, and patent application Ser. No. 2001-191029 filed in Japan on Jun.25, 2001, which are herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a motor vehicle such as an electric vehiclethat acquires driving power for running from a high voltage power supplyand includes a high voltage system shut-off device that shuts off a highvoltage electric system in case of emergency.

2. Description of the Related Art

An electric vehicle acquires driving power for running from a powersupply of a considerably higher voltage (several hundred volt) than abattery (usually 12 bolt) installed in a normal motor vehicle. Thus, theelectric vehicle is required to take measures to prevent leakage of ahigh voltage power supply in case of emergency, and accordingly, avariety of techniques have been proposed.

For example, Japanese Laid-Open Utility Model Publication (Kokai) No.61-202101 has disclosed an electric vehicle that is capable of shuttingoff the flow of electric current from a power supply to a drive unitupon detection of a collision.

Further, Japanese Laid-Open Patent Publication (Kokai) No. 09-284901 hasdisclosed the technique of disconnecting batteries from an electricvehicle to prevent leakage of a high voltage, and reconnecting thebatteries to the electric vehicle if the vehicle is only slightlydamaged.

A sensor for detecting a collision of a vehicle, however, determineswhether the vehicle has collided or not according to impact applied tothe sensor itself, and therefore, the sensor may determine that thevehicle has collided even in a case where the vehicle has not reallycollided. In this case, even through the vehicle is able to continuerunning, the flow of electric current from a power supply is shut off tostop a drive unit for running the vehicle. This disenables the vehicleto run, and therefore, the vehicle stops on the moment.

Moreover, if a sensor for detecting a collision of the vehicle and anelectric circuit thereof have failed, the flow of electric current fromthe power supply to a drive unit is controlled according to falseinformation, and even if the vehicle has not really collided, the flowof electric current from the power supply to the drive may be shut offto disenable the vehicle to run.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a motorvehicle such as an electric vehicle, which acquires driving power forrunning from a high voltage power supply and includes a high voltagesystem shut-off apparatus, which promptly shuts off the power supply ifthe vehicle has collided, and surely enable the vehicle to run withoutshutting off the power supply if the vehicle has not collided.

To attain the above object, the present invention provides a motorvehicle that acquires driving power for running from a high voltagepower supply, comprising: a feeding circuit breaking and connectingdevice that is provided in a feeding circuit, connecting a power supplyto a motor, to break and connect the feeding circuit; a collisiondetecting device that is provided in the motor vehicle to detect acollision of the motor vehicle; a feeding circuit control device that isresponsive to a collision detection signal from the collision detectingdevice, for controlling breaking of the feeding circuit by the feedingcircuit breaking and connecting device; and an inhibiting device that isprovided in the motor vehicle to detect an operating condition of themotor vehicle and inhibit the feeding control device from operating.

BRIEF DESCRIPTION OF THE DRAWINGS

The name of this invention, as well as other objects and advantagesthereof, will be explained in the following with reference to theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures and wherein:

FIG. 1 is a block diagram showing a principal part of a motor vehicleand a high voltage system shut-off apparatus thereof according to afirst embodiment of the present invention;

FIG. 2 is a flow chart showing a main routine of operations of the highvoltage system shut-off apparatus according to the first embodiment ofthe present invention;

FIG. 3 is a flow chart showing a sub routine of operations of the highvoltage system shut-off apparatus according to the first embodiment ofthe present invention;

FIG. 4 is a flow chart showing a main routine of operations of a highvoltage system shut-off apparatus according to a second embodiment ofthe present invention;

FIG. 5 is a block diagram showing a principal part of a motor vehicleand a high voltage system shut-off apparatus thereof according to athird embodiment of the present invention;

FIG. 6 is a flow chart showing a main routine of operations of a highvoltage system shut-off apparatus according to the third embodiment ofthe present invention;

FIG. 7 is a flow chart showing a sub routine of operations of a highvoltage system shut-off apparatus according to the third embodiment ofthe present invention;

FIG. 8 is a block diagram showing a principal part of a motor vehicleand a high voltage system shut-off apparatus thereof according to afourth embodiment of the present invention; and

FIG. 9 is a flow chart showing operations of the high voltage systemshut-off apparatus according to the fourth embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiment of the present invention will now be described indetail with reference to the accompanying drawings.

A motor vehicle according to a first embodiment is an electric vehiclethat acquires driving power for running from a high voltage power supplyof several hundred volt, for example. As shown in FIG. 1, the motorvehicle has a motor 1 for rotating driving wheels to run the vehicle. Tosupply power to the motor 1, the motor vehicle is comprised of a mainbattery 2 to which are serial-connected a number of 12-bolt batteries, amain contactor 3 (feeding circuit breaking and connecting device) thatis connected to the main battery 2, and a motor controller 4 that isdisposed between the main contactor 3 and the motor 1.

With this arrangement, the motor 1 is rotated by the power supplied fromthe main battery 2 via the main contactor 3 under the control of a motorcontroller 4. It should be noted that the main battery 2 corresponds toa high voltage power supply, and the main battery 2, main contactor 3,motor controller 4, and motor 1, and a circuit 5 that extends from themain battery 2 to the motor controller 4 and the motor 1 will begenerically referred to as a high voltage power supply system 6.

A high voltage system shut-off apparatus 10 is comprised of a collisionsensor (collision detecting device) that detects a collision of themotor vehicle, a deceleration detecting device 12 that detects thedeceleration of the motor vehicle, and a collision detection powersupply shut-off ECU (high voltage system shut-off control device;feeding circuit control device, inhibiting device) 13 that controlsbreaking of the circuit 5 of the high voltage power supply 2.

An acceleration sensor comprised of a piezo element and the like and anengineering sensor comprised of a fiber optics, an emitter, and the likemay be employed as the collision sensor 11, but this is not limitative.A conventional collision sensor provided for an air bag may be employedas the collision sensor 11 by using information from the collisionsensor directly or via an air bag ECU, for example. According to thepresent embodiment, the deceleration detecting device 12 is comprised ofa vehicle speed sensor 12 a and a deceleration calculating section 12 bthat calculates the deceleration from a vehicle speed signal suppliedfrom the vehicle speed sensor 12 a, but an acceleration sensor thatdetects the deceleration in a wide range a running direction of thevehicle may be used as the deceleration detecting device 12.

The collision detection power supply shut-off ECU 13 breaks the circuit5 of the high voltage power supply 2 via the main contactor 3 inresponse to a collision detection signal from the collision sensor 11.If a deceleration detected by the deceleration detecting device 12 doesnot become equal to or greater than a predetermined value within apredetermine period of time from the receipt of the collision detectionsignal from the collision sensor 11, the collision detection powersupply shut-off ECU 13 provides control to reconnect the circuit 5 ofthe high voltage power supply 2, which has been broken via the maincontactor 3.

With the above-described arrangement, the high voltage system shut-offapparatus according to the first embodiment of the present inventionprovides control such that the high voltage system is shut off accordingto the procedure in FIGS. 2 and 3, for example.

As shown in a main routine of FIG. 2, in response to turning-on of a keyswitch of a drive system of the motor vehicle, the main contactor 3 isturned on (step a10), a collision estimation flag is cleared (step a20),and an interrupt is permitted (step a30).

In response to the permission of the interrupt, a decelerationdetermination routine as shown in FIG. 3 is executed periodically.Specifically, as shown in FIG. 3, the deceleration calculating section12 b of the deceleration detecting device 12 receives a vehicle speedsignal from the vehicle speed sensor 12 a (step b10), calculates avehicle speed from the vehicle speed signal (step b20), and calculates adeceleration according to the calculated vehicle speed (step b30). Thecollision detection power supply shut-off ECU 13 determines whether thecalculated deceleration is not smaller than a set value (predeterminedvalue) that is determined in advance (step b40), and sets the collisionestimation flag if the calculated deceleration is equal to or greaterthan the set value (step b50). It should be noted hat the set value isdetermined in advance based on the results of an experiment and thelike.

Referring again to the main routine of FIG. 2, after the permission ofthe interrupt (step a30), the high voltage power supply shut-offapparatus determines whether the key switch is ON or not (step a40). Ifit is determined that the key switch is OFF (i.e. the key switch isturned off), the main contactor 3 is turned off (step a50) to terminatethe control. If it is determined that the key switch is ON, it is thendetermined whether collision detection information has been inputtedfrom the collision detection sensor 11 or not (i.e. whether thecollision sensor 11 is ON or not) (step s60).

If it is determined that the collision detection information has notbeen inputted from the collision sensor 11, the process returns to thestep a40. The determination in the step a40 is carried out atpredetermined intervals.

On the other hand, if it is determined the collision detectioninformation has been inputted from the collision sensor 11, it isprovisionally determined that the vehicle has collided, and the maincontactor 3 is turned off (step a70). Further, it is determined whetherthe collision estimation flag is set or not in the decelerationdetermination routine (FIG. 3) (step a80). If it is determined that thecollision estimation flag is set, it is really determined that thevehicle has collided, and the main contactor 3 is kept OFF. It is thendetermined whether the key switch is OFF or not (step a90), and if thekey switch is turned off, the control is terminated. It should be notedthat the determination in the step a90 is carried out at predeterminedintervals.

If the collision estimation flag is not set after the turning-off of themain contactor 3 due to the provisional determination that the vehiclehas collided, it is then determined whether or not a predeterminedperiod of time (in this example, one second) has elapsed with thecollision estimation flag being not set since the collision of thevehicle is detected (i.e. after the collision sensor 11 is turned on)(step a100). Even if the predetermined period of time has elapsed thewith the estimation flag being not set since the detection of thevehicle collision, it is determined that the collision of the vehiclehas been falsely detected, and the main contactor 3 is turned on (stepa110). The process then returns to the step a40.

As described above, upon receipt of the collision detection informationfrom the collision sensor 11, the collision detection power supplyshut-off ECU 13 provisionally determines that the vehicle has collided,and promptly turns off the main contactor 3 to break the circuit 5 ofthe high voltage power supply 2. This prevents vehicle fire,electrifying shock, and the like caused by the flow of electric currentfrom the high voltage power supply in the collision of the vehicle.

Moreover, if the deceleration does not become equal to or greater thanthe predetermined value in a predetermined period of time after it isprovisionally determined that the vehicle has collided, it is thendetermined that the provisional determination is false, and the maincontactor 3 is turned on to reconnect the circuit 5 of the high voltagepower supply 2. Therefore, even if the circuit of the high voltage powersupply is broken due to the malfunctioning of the collision sensor 11,the driving power for running the vehicle is ensured thereafter.

A second embodiment of the present invention will now be described withreference to the accompanying drawings.

The hardware construction of a motor vehicle and a high voltage systemshut-off apparatus according to the second embodiment is identical withthat of the first embodiment, and a description thereof is omittedherein. Only the software construction, which is different from that ofthe first embodiment, will be described below.

According to the present embodiment, it is determined that the vehiclehas collided on the following two conditions: 1) the collision sensor 11is turned on (i.e. the collision sensor 11 detects a collision of thevehicle), and 2) a deceleration detected (calculated) by thedeceleration detecting device 12 becomes equal to or greater than apredetermined value within a predetermined period of time afterturning-on of the collision sensor 11. If the two conditions 1) and 2)are satisfied, the collision detection power supply shut-off ECU 13provides control such that the main contactor 3 is turned off to breakthe circuit 5 of the high voltage power supply 2.

With the above-described arrangement, the high voltage power supplyshut-off apparatus of the motor vehicle according to the secondembodiment of the present invention controls the breaking of the highvoltage system according to the procedure in FIG. 4, for example. Itshould be noted that in FIG. 4, the same reference numerals as those ofFIG. 2 denote the same process steps, and the deceleration determinationroutine in FIG. 3 is also carried out in response to permission of aninterrupt (step a30 in FIG. 3).

As shown in a main routine of FIG. 4, in response to turning-on of a keyswitch of a drive system of the motor vehicle, the main contactor 3 isturned on (step a10), a collision estimation flag is cleared (step a20),and an interrupt is permitted (step a30) to carry out the decelerationdetermination routine in FIG. 3.

After the permission of the interrupt (step a30), the high voltage powersupply shut-off apparatus determines whether the key switch is ON or not(step a40). If the key switch is not ON (i.e. the key switch is turnedoff), the main contactor 3 is turned off (step a50) to terminate thecontrol. If the key switch is ON, it is then determined whethercollision detection information has been inputted from the collisiondetection sensor 11 or not (i.e. whether the collision sensor 11 is ONor not) (step s60). If the collision detection information has not beeninputted from the collision sensor 11, the process returns to the stepa40. The determination in the step a40 is carried out at predeterminedintervals.

On the other hand, if the collision detection information is inputtedfrom the collision sensor 11, it is determined whether the collisionestimation flag is set or not in the deceleration determination routine(FIG. 3) (step a80). If the collision estimation flag is set, it isreally determined that the vehicle has collided, and the main contactor3 is kept OFF (step a82). It is then determined whether the key switchis OFF or not (step a90), and if the key switch is turned off, thecontrol is terminated. It should be noted that the determination in thestep a90 is also carried out at predetermined intervals.

If it is determined in the step a80 that the collision estimation flagis not set, the process proceeds to the step a100 wherein it isdetermined whether or not a predetermined period of time (in thisexample, one second) has elapsed since the collision of the vehicle isdetected (i.e. after the collision sensor 11 is turned on). If thepredetermined period of time has not elapsed since the collision of thevehicle is detected, the process returns to the step a80 wherein it isdetermined whether the collision estimation flag is set or not. Thus, ifthe collision estimation flag is set within the predetermined period oftime after the collision of the vehicle is detected, it is thendetermined that the vehicle has collided, and the main contactor 3 isturned off (step a82).

On the other hand, if the collision estimation flag is not set withinthe predetermined period of time after the collision of the vehicle isdetected, it is determined that the collision of the vehicle has beenfalsely detected, and the main contactor 3 is kept ON (step a110). Theprocess then returns from the step a100 to the step a40.

As described above, on condition that the collision detectioninformation is inputted from the collision sensor 11 and the collisionestimation flag is set within a predetermined period of time after theinput of the collision detection information (i.e. the deceleration ofthe motor vehicle becomes equal to or greater than a predeterminedvalue), the collision detection power supply shut-off ECU 13 determinesthat the vehicle has collided and controls the main contactor 3.Therefore, the collision detection power supply shut-off ECU 13 is ableto correctly determine whether the vehicle has collided or not, andsurely turn off the main contactor 3 to break the circuit 5 of the highvoltage power supply 2 only in a case where the vehicle has reallycollided.

This prevents vehicle fire, electrifying shock, and the like caused bythe flow of electric current from the high voltage power supply at thetime of collision. Further, since it is correctly determined whether thevehicle has collided or not, the circuit of the high voltage powersupply is prevented from being broken according to the falsedetermination that the vehicle has collided, thus ensuring driving powerfor running the motor vehicle.

A third embodiment of the present invention will now be described.

A motor vehicle according to the present embodiment is an electric motorvehicle that acquires driving power for running from a high voltagepower supply of several hundred volts, for example. As shown in FIG. 5,the motor vehicle has a motor 301 for rotating driving wheels to run thevehicle. To supply power to the motor 301, the motor vehicle iscomprised of a main battery 302 to which are serial-connected a numberof 312-bolt batteries, a main contactor 203 that is connected to themain battery 302, and a motor controller 304 that is disposed betweenthe main contactor 303 and the motor 301.

With this arrangement, the motor 301 is rotated by the power suppliedfrom the main battery 302 via the main contactor 303 under the controlof a motor controller 304. It should be noted that the main battery 302corresponds to a high voltage power supply, and the main battery 302,main contactor 303, and motor controller 304, and a circuit that extendsfrom the main battery 302 to the motor controller 304 via the maincontactor 303 will be generically referred to as a high voltage powersupply system 6.

A high voltage system shut-off apparatus 310 is comprised of a collisionsensor (collision detecting device) 311 that detects a collision of themotor vehicle, a deceleration detecting device 312 that detects thedeceleration of the motor vehicle, a high voltage system shut-offcontrol section 314 that controls breaking of the circuit 305 of thehigh voltage power supply 302, a power supply circuit breaking conditiondetermination section 315 that determines whether the circuit 305 of thehigh voltage power supply 302 has been broken or not, an indicatingdevice that supplies information indicative of whether the circuit 305of the high voltage power supply 302 has been broken or not, a remotecontrol receiver 321 that serves as a high voltage system manualshut-off device for manually breaking the circuit 305 of the highvoltage power supply 302, and an in-vehicle power supply switch 322.

An acceleration sensor comprised of a piezo-element or the like, or anengineering sensor that is comprised of a fiber optics, an emitter, andthe like may be employed as the collision sensor 311, but this is notimitative. A conventional collision sensor provided for an air bag maybe employed as the collision sensor 311 by using information from thecollision sensor directly or via an air bag ECU.

The high voltage system shut-off control section 314 and the powersupply circuit breaking condition determination section 315 arefunctional component parts of the collision detection power supplyshut-off ECU 313.

The high voltage system shut-off section 314 breaks the circuit 305 ofthe high voltage power supply 302 via the main contactor 303 in responseto the collision detection signal from the collision sensor 311.However, if the motor vehicle does not decelerate by a predeterminedvalue or greater within a predetermined period of time t1 from a timepoint when the collision detection signal is received from the collisionsensor 11, the vehicle has not really collided. In this case, the highvoltage system shut-off device 314 determines that the collision of thevehicle has been falsely detected by the collision sensor 311, andreconnects the circuit 305 of the high voltage power supply 302 via themain contactor 303.

Thus, according to the present embodiment, if the deceleration of themotor vehicle becomes equal to or greater than a predetermined valuewithin the predetermined period of time t1 after the collision isdetected by the collision sensor 311, it is determined that the motorvehicle has really collided. On the other hand, if the deceleration ofthe motor vehicle does not become equal or greater than thepredetermined value within the predetermined period of time t1 after thecollision is detected by the collision sensor 311, it is determined thatthe motor vehicle has not really collided. In an alternative form, itmay be determined that the motor vehicle has really collided if thevehicle speed is kept at 0 for a predetermined period of time tt1 orlonger in a predetermined period of time t2 (t2>t1) after the collisionis detected by the collision sensor 311, and it may be determined thatthe motor vehicle has not really collided if the vehicle speed is notkept at 0 for the predetermined period of time tt1 or longer within thepredetermined period of time t2 (t2>t1) after the collision is detectedby the collision sensor 311.

The power supply circuit breaking condition determination section 315determines whether the deceleration of the motor vehicle becomes equalto or greater than the predetermined value within the predeterminedperiod of time t1 after the collision is detected by the collisionsensor 311. If the vehicle speed is kept at 0 for a predetermined periodof time tt2 (tt2 may be equal to tt1) in a predetermined period of timet3 (t3>t1 or t3=t2) after the collision is detected by the collisionsensor 311, the power supply circuit breaking condition determinationdevice 315 determines whether the circuit of the high voltage powersupply has been broken by the high voltage system shut-off controlsection 314 according to current-carrying information supplied from themain contactor 303. The purpose of determining whether or not thevehicle speed is kept at 0 for the predetermined period of time tt2 orlonger is to determine and indicate whether the circuit of the highvoltage power supply has been broken or not.

In an alternative form, in the case where it is determined that themotor vehicle has not really collided if the vehicle speed has kept at 0for the predetermined period of time tt1 or longer in the predeterminedperiod of time t2 after the collision, it may be determined that thevehicle has really collided if the vehicle speed has been kept at 0 forthe predetermined period of time tt1 in the predetermined period of timet2 after the detection of the collision, and it may be determinedwhether the circuit of the high voltage power supply has been broken bythe high voltage system shut-off control section 314 according to thecurrent-carrying information supplied from the main contactor 303.

The indicating device 316 is comprised of a fail indicator 318, a hazardlamp 319, and an indication control section 317 that controls the failindicator 318 and the hazard lamp 319. The indication control section317 is a functional component part of the collision detection powersupply shut-off ECU 313. If the power supply circuit breaking conditiondetermination section 315 determines whether the circuit of the highvoltage power supply has been broken or not after the collision, theindication control device 317 provides control such that the failindicator 318 and the hazard lamp 319 indicate whether the circuit ofthe high voltage power supply has been broken or not according to theresult of the determination by the power supply circuit breakingcondition determination circuit 315.

Specifically, the fail indicator 318 and the hazard lamp 319 indicateinformation in different manners according to whether the circuit of thehigh voltage power supply is broken or not after the collision. Forexample, if the fail indicator 318 is implemented by an indicator lamp,it is turned on only in the case where the circuit of the high voltagepower supply is not broken after the collision, but is turned off inother cases. Further, the hazard lamp 319 may be flashed (specialflashing) in a different rhythm from normal flashing in the case wherethe circuit of the high voltage power supply is not broken after thecollision.

In an alternative form, the information may be indicated by a soundgenerated by a buzzer or the like, and more preferably, the informationis indicated by a voice representing the message “high voltage powersupply circuit is connected”, for example.

It goes without saying that if the circuit of the high voltage powersupply is broken after the collision, it may be indicated by the failindicator 318, the hazard lamp 319, the buzzing sound, the voice, andthe like. For example, if the fail indicator 318 is set to continuouslylight up in the case where the circuit of the high voltage power supplyhas not been broken since the collision, it may be flashed when thecircuit of the high voltage power supply is broken. If the hazard lamp318 is set to be flashed in a particular way in the case where thecircuit of the high voltage power supply has not been broken since thecollision, it may be flashed in a normal way if the circuit of the highvoltage power supply has been broken. Further, the voice may representthe message “high voltage power supply circuit has been broken due tocollision”.

The remote control receiver 321 and the in-vehicle power supply switch322 serving as the high voltage system manual shut-off device areoperated on predetermined conditions. According to the presentembodiment, the remote control receiver 321 and the in-vehicle powersupply switch 322 are operated in the case where the followingconditions are satisfied: 1) the motor vehicle has collided, 2) thecircuit of the high voltage power supply has not been shut off, and 3)the motor vehicle has stopped (the vehicle speed has been kept at 0 fora predetermined pored of time).

These operating conditions 1), 2) and 3) are intended to restrict themanual breaking of the high voltage power supply circuit to the minimumso as to prevent the high voltage power supply circuit from being shutoff excessively. According to the present embodiment, it is necessary tosatisfy all of the conditions 1) the motor vehicle has collided, 2) thecircuit of the high voltage power supply has not been shut off, and 3)the motor vehicle has stopped (the vehicle speed has been kept at 0 fora predetermined pored of time). In particular, the condition 3) isintended to prevent the circuit of the high voltage power supply frombeing broken while the vehicle is running backward, so that the vehiclecan be prevented from being disenabled to run.

If the above operating conditions are satisfied, the remote controlreceiver 321 is responsive to a shut-off instruction signal from anexternal remote control (not illustrated), for outputting a signal forinstructing the main contactor 303 to break the circuit of the highvoltage power supply or turns off another power supply connecting switch(shut off the power supply). If the in-vehicle power supply switch 322is operated in the case where the above operating conditions aresatisfied, it outputs a signal for instructing the main contactor 303 tobreak the circuit of the high voltage power supply or turns off anotherpower supply connecting switch (shut off the power supply).

With the above-described arrangement, the high voltage system shut-offapparatus of the motor vehicle according to the third embodimentcontrols the shut-off of the high voltage system and indicates thebreaking condition as shown in FIGS. 6 and 7, for example.

As shown in a main routine of FIG. 6, in response to turning-on of a keyswitch of a drive unit of the motor vehicle, the main contactor 303 isturned on (step a3010), a collision estimation flag is cleared (stepa3020), and an interrupt is permitted (step a3030).

In response to the permission of the interrupt, a decelerationdetermination routine as shown in FIG. 7 is executed periodically.Specifically, as shown in FIG. 7, a vehicle speed signal is inputtedfrom the vehicle speed sensor 312 (step b3010), a vehicle speed iscalculated from the vehicle speed signal (step b3020), and adeceleration is calculated according to the calculated vehicle speed(step b3030). The collision detection power supply shut-off ECU 313determines whether the calculated deceleration is not smaller than a setvalue (predetermined value) that is determined in advance (step b3040),and sets the collision estimation flag if the calculated deceleration isequal to or greater than the set value (step b3050). It should be notedthat the set value is determined in advance based on the results of anexperiment and the like.

Referring again to the main routine of FIG. 6, after the permission ofthe interrupt (step a3030), the high voltage power supply shut-offapparatus determines whether the key switch is ON or not (step a3040).If the key switch is not ON (i.e. the key switch is turned off), themain contactor 303 is turned off (step a3050) to terminate the control.If the key switch is ON, it is determined whether collision detectioninformation has been inputted from the collision detection sensor 311 ornot (i.e. whether the collision sensor 311 is ON or not) (step s3060).

If it is determined that the collision detection information has notbeen inputted from the collision sensor 311, the process returns to thestep a3040. It should be noted that the determination in the step a3040is carried out at predetermined intervals.

On the other hand, if it is determined that the collision detectioninformation has been inputted from the collision sensor 311, it isprovisionally determined that the vehicle has collided, and the maincontactor 303 is turned off (step a3070). Further, it is determinedwhether the collision estimation flag is set or not in the decelerationdetermination routine (FIG. 7) (step a3080).

If the collision estimation flag is set, it is really determined thatthe vehicle has collided, and the main contactor 3 is kept OFF. It isthen determined whether the vehicle speed V is lower than a micro speedvalue V0 (i.e. the vehicle has stopped) or not (step a3082). If it isdetermined that the vehicle speed V is not lower than the micro speedvalue V0, in other words, if the vehicle has not stopped, a timer isreset to 0 (step a3084) and the process returns to the step a3040.

If it is determined that the vehicle speed V is lower than the microspeed value V0, in other words, if the vehicle has stopped, the valueindicated by the timer is incremented by a predetermined value α(control cycle) and the process returns to the step a3086 wherein it isdetermined whether the value indicated by the timer has reached apredetermined period of time T1 or not. If it is determined that thevalue indicated by the timer has not reached a predetermined period oftime T1, the process returns to the step a3040.

If it is determined in the step a3086 that the value indicated by thetimer has not reached the predetermined period of time T1, it indicatesthat the vehicle has continuously stopped for the predetermined periodof time T1. It is then determined whether a power supply shut-off signalhas been received or not (step a3090). If the power supply shut-offsignal has been received, information indicating that the power supplyhas been shut off is supplied by the fail indicator 318, the hazard lamp319, the buzzer, the voice, and the like (step a3092). If the powersupply shut-off signal has not been received, information indicatingthat the power supply has not been shut off is supplied by the failindicator 318, the hazard lamp 319, the buzzer, the voice, and the like(step a3094).

Since passengers or rescuers are notified of whether the power supply(high voltage power supply) has been shut off or not since the stop ofthe vehicle in the case of collision, they can cope with the accidentwhile recognizing whether the circuit of the high voltage power supplyhas been broken or not. If the circuit of the high voltage power supplyhas been broken, they can promptly cope with the accident without beingconcerned about leakage, and if the circuit of the high voltage powersupply has not been shut off, they can cope with the accident whilebeing concerned about leakage.

In the case where the motor vehicle has collided but the circuit of thehigh voltage power supply has not been shut off, if the high voltagepower supply circuit is broken by operating a remote control switch(remote control), not shown, the remote control receiver 321 isresponsive to a shut-off instruction signal from the remote control, foroutputting a signal for instructing the main contactor 303 to break thecircuit of the high voltage power supply or turning off another powersupply connecting switch (shuts off the power supply). This breaks highvoltage power supply circuit, and enables rescuers to promptly cope withthe accident without being concerned about leakage.

In the case where the motor vehicle has collided but the circuit of thehigh voltage power supply has not been broken, a passenger on the motorvehicle operates the in-vehicle power supply switch 322 to output asignal for instructing the main contactor 303 to break the circuit ofthe high voltage power supply or turns off another power supplyconnecting switch (shut-off the power supply). This breaks the highvoltage power supply circuit, and enables the passenger on the motorvehicle to promptly cope with the accident without being concerned aboutleakage.

Further, the high voltage power supply circuit is broken by the remotecontrol switch or the like on conditions that the motor vehicle hascollided, the circuit of the high voltage power supply has not been shutoff, and the vehicle has stopped (the vehicle speed is kept at 0 for apredetermined period of time), and this prevents the circuit of the highvoltage power supply from being broken to inhibit the motor vehicle frombeing disenabled to run while it is running backward.

On the other hand, if the collision estimation flag is not set after theturning-off of the main contactor 303 due to the provisionaldetermination that the vehicle has collided, it is determined whether apredetermined period of time (in this example, one second) has elapsedwith the collision estimation flag being not set after the collision ofthe vehicle is detected (i.e. after the collision sensor 11 is turnedon) (step a3100). If the predetermined period of time has elapsed withthe collision estimation flag being not set after the collision of thevehicle is detected, it is determined that the collision of the vehiclehas been falsely detected, and the main contactor 303 is turned on (stepa3110). The process then returns to the step a3040.

As described above, in response to the input of the collision detectioninformation from the collision sensor 311, the collision detection powersupply shut-off ECU 313 provisionally determines that the vehicle hascollided, and immediately turns off the main contactor 303 to break thecircuit 305 of the high voltage power supply 302. This prevents vehiclefire, electrifying shock, and the like caused by the flow of electriccurrent from the high voltage power supply at the time of collision.

Moreover, if the deceleration does not become equal to or greater thanthe predetermined value after it is provisionally determined that thevehicle has collided, it is determined that the provisionaldetermination is false, and the main contactor 303 is turned on toreconnect the circuit 305 of the high voltage power supply 302.Therefore, even if the circuit of the high voltage power supply isbroken due to the false determination by the collision sensor 11, thedriving power for running the vehicle can be ensured thereafter.

A motor vehicle according to the present embodiment is an electric motorvehicle that acquires driving power for running from a high voltagepower supply of several hundred volt, for example. As shown in FIG. 8,the motor vehicle has a motor 401 for rotating driving wheels to run thevehicle. To supply power to the motor 401, the motor vehicle iscomprised of a main battery 402 to which are serial-connected a numberof 12-bolt batteries, a main contactor 403 that is connected to the mainbattery 402, and a motor controller 404 that is provided between themain contactor 403 and the motor 401.

With this arrangement, the motor 401 is rotated by the power suppliedfrom the main battery 402 via the main contactor 403 under the controlof a motor controller 404. It should be noted that the main battery 402corresponds to a high voltage power supply, and the main battery 402,main contactor 403, motor controller 404, and motor 401, and a circuit405 that extends from the main battery 402 to the motor controller 404and the motor 401 will be generically referred to as a high voltagepower supply system 406.

A high voltage system shut-off apparatus 410 according to the presentembodiment is comprised of a collision sensor (collision detectingdevice) 411 that detects a collision of the motor vehicle, adeceleration detecting device (not illustrated, but similar to the oneillustrated in FIG. 1) that detects the deceleration of the motorvehicle, a collision detection power supply shut-off ECU (high voltagesystem shut-off control system) 413 that controls breaking of thecircuit 405 of the high voltage power supply 402, a power supplyshut-off control fail indicator (failure indicating device) 420. Thecollision detection power supply shut-off ECU 413 is provided with afailure determination section 414 and a high voltage system breaking andconnection control section 415.

An acceleration sensor that outputs a voltage corresponding to theacceleration or deceleration, e.g. an acceleration sensor using a piezoelement or the like may be employed as the collision sensor 411. If themotor vehicle collides, the motor vehicle decelerates to an extent thatis impossible when the motor vehicle is running normally. Thus, inresponse to a voltage signal indicative of a voltage equal to or higherthan a predetermined value (the voltage equal to or greater than thepredetermined value is regarded as a collision detection signal), it maybe determined that the motor vehicle has collided. Namely, the collisionsensor 411 outputs the collision detection signal only when thedeceleration of the motor vehicle is equal to or greater than thepredetermined value.

It should be noted that a large deceleration occurs in an extremelyshort period of time when the motor vehicle collides, the collisiondetection signal (signal indicative of a voltage equal to or higher thanthe predetermined value) is outputted from the collision sensor 411 onlyin such an extremely short period of time.

There is no intention to limit the collision sensor 411 to the one ofthe present embodiment. For example, an engineering sensor that iscomprised of a fiber optics, an emitter and the like may be employed asthe collision sensor 411, insofar as it is capable of being responsiveto the deceleration occurring in collision of the motor vehicle. Aconventional collision sensor provided for an air bag may be employed asthe collision sensor 411 by using information from the collision sensordirectly or via an air bag ECU.

The failure determination section 414 determines that the collisionsensor 411 has failed if the collision detection signal is outputtedfrom the collision sensor for a predetermined period of time or longer.As described above, the collision sensor 411 outputs the collisiondetection signal only when the motor vehicle decelerates to an extentthat is impossible when the motor vehicle is normally running. Moreover,the motor vehicle decelerates to such an extent only if it has collided.Upon collision, the vehicle decelerates only in an extremely shortperiod of time. Thus, the collision detection signal is outputted fromthe collision sensor 411 only in an extremely short period of time inwhich the motor vehicle considerably decelerates due to the collision.Therefore, if the collision detection signal is outputted from thecollision sensor 411 for a predetermined period of time (determinationtime) or longer, the failure determination section 414 determines thatthe collision sensor 411 has failed.

It should be noted that the predetermined period of time (determinationtime) is set to be evidently longer than a period of time in which alarge deceleration of not less than a predetermined value is assumed tooccur in collision, but is set to be not excessively long (e.g. twoseconds). Namely, insofar as a failure of the collision sensor 411 hasnot yet been detected, it is assumed first that the collision sensor 411is normal when the collision sensor 411 outputs the collision detectionsignal, and the main contactor 403 is turned off. If the collisionsensor 311 outputs the collision detection signal for an excessivelylong period of time, it is determined that the collision sensor 411 hasfailed, and the main contactor 403 is turned on to surely enable thevehicle to run.

If the collision sensor 411 outputs the collision detection signal dueto a failure of the collision sensor 411, it is determined first thatthe collision sensor 411 is normal, and the driving power for running islost temporarily to turn off the main contactor 403. The main contactor403 is then turned on to ensure the driving power for running thevehicle. In this case, the driving power for running is lost since thecollision sensor 411 starts outputting the collision detection signaluntil it is determined that the collision detection signal is outputteddue to the failure of the collision sensor 411 (determination time), anda period of time in which the driving power for running is lost ispreferably as short as possible. It goes without saying that thedetermination time should be extended to some extent in order toaccurately determine whether the collision detection signal is resultingfrom a collision of vehicle or a failure of the collision sensor 411.From this standpoint, an appropriate period of time (e.g. two seconds)should be set as the determination time.

The high voltage system breaking and connection control section 415provides control of current-carrying such that the circuit of the highvoltage power supply 402 is broken in response to the collisiondetection signal from the collision sensor 411, and if it is determinedthat the failure determination section 414 determines that the collisionsensor 411 has failed after the breaking of the circuit, the brokencircuit of the high voltage power supply 402 is reconnected.

The power supply shut-off control fail indicator (failure indicatingdevice) 420 is comprised of a valve that is controlled by the collisiondetection power supply shut-off ECU 413. If the failure determinationsection 414 determines that the collision sensor 411 has failed, thepower supply shut-off control fail indicator 420 is lighted under thecontrol of the collision detection power supply shut-off ECU 413 tonotify a driver of that fact. More specifically, as is the case withother fail indicators, the power supply shut-off control fail indicator420 is temporarily turned on just after an engine key switch is turnedon. Thereafter, the power supply shut-off control fail indicator 420 isturned off if the failure determination section 414 does not output afailure determination signal indicative of a failure of the collisionsensor 411, and the power supply shut-off control fail indicator 420 iskept ON if the failure determination section 414 outputs a failuredetermination signal indicative of a failure of the collision sensor411.

With the above-described arrangement, the high voltage system shut-offapparatus of the motor vehicle according to the fourth embodiment of thepresent invention, which is constructed in the above-mentioned manner,controls the shut-off of the high voltage system as shown in FIG. 9, forexample.

As shown in FIG. 9, in response to turning-on of a key switch of driveunit of the motor vehicle, the power supply shut-off control failindicator 410 is turned on (step S10), and the main contactor 403 isturned on (step S20).

The process then proceeds to a step S30 wherein it is checked whetherthe collision sensor 411 has failed or not (i.e. a determination signalfrom the failure determination device 414 is captured). According to thedetermination signal from the failure determination section 414, it isdetermined whether the collision sensor 411 has failed (shut off down)or not (step S40).

If it is determined that the collision sensor 411 has not failed, thefail indicator 410 is turned off (step S50) and it is determined whetherthe key switch is ON or not (step S60). If it is determined that the keyswitch is ON, the process proceeds to a step S100, and if it isdetermined that the key switch is OFF, the process proceeds to a stepS90 wherein the main contactor 403 is turned off to terminate thecontrol.

On the other hand, if it is determined that the collision sensor 411 hasfailed, the fail indicator 10 is turned on or kept on (step S70) and itis determined whether the key switch is OFF or not (step S80). If it isdetermined that the key switch is ON, the process returns to the stepS30 upon elapse of a predetermined period of time (control cycle). If itis determined that the key switch is OFF, the process proceeds to thestep S90 wherein the main contactor 403 is turned off to terminate thecontrol.

In the step S100, it is determined whether the collision sensor 411 isON or not, i.e. whether the collision sensor 411 is outputting thecollision detection signal or not. If it is determined that thecollision sensor 411 is OFF (i.e. the collision sensor 411 is notoutputting the collision detection signal), the process returns to thestep S30 upon elapse of a predetermined period of time (control cycle).If it is determined that the collision sensor 411 is ON (i.e. thecollision sensor 411 is outputting the collision detection signal), theprocess proceeds to a step S110 wherein the main contactor 403 is off,and the process then proceeds to a step S120.

In the step S120, it is determined whether the collision sensor 411 hasbeen kept ON for a predetermined period of time (in this example, twoseconds) or not. If the collision sensor 411 has not been kept for thepredetermined period of time, it is determined that the collision sensor411 has not failed. The fail indicator 410 is then turned off (stepS130) and it is determined whether the key switch is OFF or not (stepS140). If it is determined that the key switch is ON, the processreturns to the step S120 upon elapse of a predetermined period of time(control cycle), and if it is determined that the key switch is OFF, theprocess proceeds to a step S150 wherein the main contactor 403 is turnedoff to terminate the control.

On the other hand, if the collision sensor 411 has been kept ON for thepredetermined period of time, it is determined that the collision sensor411 has failed, and the fail indicator 410 is turned on (step S160). Themain contactor 403 is turned on (step S170), and it is determinedwhether the key switch is OFF or not (step S180). If it is determinedthat the key switch is ON, the process returns to the step S180 uponelapse of a predetermined period of time (control cycle), and if it isdetermined that the key switch is OFF, the process proceeds to a stepS190 wherein the main contactor 403 is turned off to terminate thecontrol.

Specifically, if the collision sensor 411 is switched from the OFF stateto the ON state in a certain control cycle, the timer starts counting anelapsed time. The counting is continued insofar as the collision sensor411 is not turned off. If the collision sensor 411 has been turned onwithout fail in response to the actual collision of the motor vehicle,the collision sensor 411 outputs an ON signal only a short period oftime when the motor vehicle collides, and the collision sensor 411 isthen turned off. Therefore, the collision sensor 411 is not kept ON forthe predetermined period of time, and until the key switch is turnedoff, the fail indicator 410 is kept OFF in the step S130.

On the other hand, if the collision sensor 411 is turned on due to thefailure, it is kept ON thereafter. Thus, if the collision sensor 411 hasbeen kept ON for a sufficiently longer period of time (in this example,two seconds) than a period of time in which a greater deceleration thana predetermined value occurs in collision, it is determined that thecollision sensor 411 has failed, and the fail indicator 410 is turned on(step S160). The main contactor 403 is then turned on (step S170), andthe fail indicator 410 is kept ON and the main contactor is kept ONuntil the key switch is turned off.

If the collision sensor 411 has failed as mentioned above, the keyswitch is turned off and then turned on. After carrying out the processin the steps S10 and S20, the fail indicator 410 is turned on, and themain contactor 403 is turned on. The process then proceeds to the stepS30 wherein it is determined that the collision sensor 411 has failed.The process then proceeds to the step S70 wherein the fail indicator 410is kept ON and the main contactor 403 is kept ON.

Therefore, the fail indicator 410 and the main contactor 403 are kept ONuntil it is determined in the step S80 that the key switch is OFF.

As described above, if the collision sensor 411 is normal, a collisionof the motor vehicle is detected according to an output from thecollision sensor 411 to shut off the high voltage power supply. Thisprevents vehicle fire, electrifying shock, and makes is possible tosmoothly cope with the accident.

If the collision sensor 411 has failed, the fail indicator 410 is turnedon to inform a driver or the like of the fact that the collision sensor411 has failed, while the main contactor 403 is kept on to surely enablethe vehicle to run.

In particular, according to the present embodiment, if the collisionsensor 411 outputs the collision detection signal, the main contactor403 is turned off based on the assumption that the collision sensor 411is normal before it is determined whether the collision detection signalresults from the failure of the collisions sensor 411 (i.e. thecollision detection signal does not result from a collision of thevehicle). Therefore, the high voltage power supply is shut offimmediately after the vehicle collides with the collision sensor 411being normal. This prevents vehicle fire, electrifying shock, and thelike.

The failure determination section 414 determines that the collisionsensor 411 has failed if the collision sensor 411 has outputted thecollision detection signal for a predetermined period of time, the highvoltage system breaking and connection control device 415 providescontrol of current-carrying such that the main contactor 403 is broughtinto the ON state again to reconnect the broken circuit of the highvoltage power supply 402.

On this occasion, the failure determination section 414 determineswhether the collision detection signal results from the failure of thecollision sensor 411 in an appropriate determination time (e.g. twoseconds). Therefore, if the collision sensor 411 has failed, the periodof time (determination time) in which the driving power for running islost is reduced as much as possible to prevent the running of the motorvehicle from being obstructed, while it is clearly determined whetherthe collision detection signal results from a collision of the motorvehicle or a failure of the collision sensor 411.

It should be understood, however, that there is no intention to limitthe invention to the specific forms disclosed, but on the contrary, theinvention is to cover all modifications, alternate constructions andequivalents falling within the spirit and scope of the invention asexpressed in the appended claims.

1. A motor vehicle driven by a motor run by power, comprising: a feedingcircuit breaking and connecting device provided in a feeding circuitthat provides a power supply to a motor, for breaking and connecting thefeeding circuit; a collision detecting device for detecting a collisionof said motor vehicle; a failure determination device that determines afailure of said collision detecting device; and a high voltage systemshut-off control device for controlling said feeding circuit breakingand connecting device to break the feeding circuit in response to saidcollision detecting device detecting a collision of said motor vehicle,and to restore the connection of the feeding circuit in response to saidfailure determination device determining that said collision detectingdevice failed.
 2. A motor vehicle according to claim 1, wherein: saidcollision detecting device outputs a collision signal if a decelerationof said motor vehicle has become equal to or greater than apredetermined value.
 3. A motor vehicle according to claim 1, wherein:said collision detecting device is a collision detecting device for anair bag provided in said motor vehicle.
 4. A motor vehicle according toclaim 1, wherein: if said collision detecting device has output thecollision detection signal for a predetermined period or longer, saidfailure determination device determines that said collision detectionsignal failed.
 5. A motor vehicle according to claim 4, furthercomprising: a failure indicating device that informs a driver of afailure of said collision detecting device upon said collision detectingdevice failing.
 6. A motor vehicle according to claim 4, wherein saidcollision detection signal is output to said high voltage systemshut-off control device if a deceleration of said motor vehicle hasbecome equal to or greater than a predetermined value.
 7. A motorvehicle according to claim 6, wherein said predetermined period is setlonger than a period in which a larger deceleration of not less thansaid predetermined value is assumed to occur during a collision.
 8. Amethod of controlling supply of power to a motor of a motor vehicle thatis driven by the motor run by power, comprising the steps of: detectinga collision of said motor vehicle with a collision detecting device;breaking a feeding circuit to the motor with a feeding circuit breakingand connecting device upon detecting a collision of said motor vehicle;determining whether a collision signal from said collision detectingdevice is false; and controlling the feeding circuit breaking andconnecting device to restore the connection of said feeding circuit ifthe collision signal from said collision detecting device is false.
 9. Amethod according to claim 8, wherein: the collision signal is false whenthe collision detecting device fails, whereupon the power supply to saidmotor is restored.